Multilevel infrared coupling of excitons in quantum-wellsemiconductors

摘要

We study the effects of multilevel mixing of the 1s and 2s statesnof the E1-HH1 and E2-HH1 excitons in the emission spectra of an undopednquantum well. This is done by investigating the E1-HH1 exciton emissionnspectra in the presence of an intense CO2 laser nearnresonance with the transition between El and E2. Our results show that,ndepending on the frequency of the CO2 laser, these spectranare quenched peculiarly. We explain these phenomena based on thenfrequency dependence of the mixing configurations of the exciton statesnand infrared enhancement of the nonradiative decay rates of E1-HH1nexcitons. We also study the effect of the nonparabolicity of the holensubband (HH1) in the infrared mixing of the E1-HH1 and E2-HH1 excitons